This invention relates generally to printed circuit boards (PCB""s). In particular, the present invention is an assembly for mounting a bus termination board, having surface-mount resistors, to a connector arrangement on a PCB to provide bus termination of a signal line. The mounting assembly includes a pressure plate that surrounds the surface-mount resistors of the termination board and protects these resistors from the significant forces required to provide sufficient electrical contact between the termination board and the connector arrangement on the PCB.
Printed circuit boards (PCB""s) with electrical components are widely used in the electronics industry in a variety of products including computers, televisions and telecommunication devices. These devices often make use of signal lines that are mounted to the PCB""s using a connector arrangement. In these devices it is common to provide bus termination of these signal lines at the connector arrangement using resistor packages. Typically these resistor packages are held in place on the connector arrangement using a bus termination clamping arrangement. This bus termination clamping arrangement imparts a significant clamping force to the resistor packages that is sufficient to provide the necessary electrical contact between the resistor packages and the PCB through the connector arrangement.
Although this system provides adequate bus termination of a signal line at the connector arrangement of the PCB, there are some drawbacks. For example, these resistor packages typically must be individually hand loaded onto the connector arrangement of the PCB which is labor intensive and impractical for mass production. Moreover, these resistor packages are often quite fragile since they are not rigidly attached to the connector arrangement. As such, these resistor packages, that provide bus termination at the PCB, are susceptible to inadvertent damage caused by the significant clamping forces, imparted by the bus termination clamping arrangement, necessary to provide sufficient electrical contact between the resistor packages and the connector arrangement. Moreover, these resistor packages are susceptible to inadvertent damage during routine handling of the PCB.
There is a need for an improved assembly for mounting resistors to a connector arrangement on a PCB to provide bus termination of a signal line. In particular, there is a need for a bus termination mounting assembly that makes use of resistors surface mounted to a bus termination board to permit mass production and eliminate the need to individually hand load the resistors onto the connector arrangement of the PCB. In addition, the bus termination mounting assembly should protect these surface-mount resistors from the significant forces necessary to provide sufficient electrical contact between the surface-mount resistors of the termination board and the connector arrangement of the PCB. Moreover, the bus termination mounting assembly should protect the surface-mount resistors from inadvertent damage caused by routine handling of the PCB. Lastly, the bus termination mounting assembly should be relatively easy and inexpensive to manufacture.
The present invention is a mounting assembly for providing bus termination of at least one signal line on a printed circuit board (PCB). The mounting assembly includes a connector arrangement, a bus termination device and a clamping mechanism. The connector arrangement includes a plurality of electrical interface elements configured to provide electrical communication between the connector arrangement and the at least one signal line of the PCB when the connector arrangement is secured to the PCB. The bus termination device is configured to be received by the connector arrangement. The bus termination device has a plurality of corresponding electrical interface elements for engaging the plurality of electrical interface elements of the connector arrangement for providing bus termination of the signal line of the PCB. The clamping mechanism is engageable with the bus termination device for maintaining electrical contact between the plurality of corresponding electrical interface elements of the bus termination device and the plurality of electrical interface elements of the connector arrangement. The clamping mechanism secures the connector arrangement and bus termination device to the PCB.
In one aspect of the present invention, the bus termination device includes a bus termination board having a first surface and an opposite second surface. The first surface includes a plurality of spaced resistor packages operatively connected to the plurality of corresponding electrical interface elements on the second surface of the bus termination board. A pressure plate member is interposed between the clamping mechanism and the bus termination board, the pressure plate member protects the plurality of spaced resistor packages from damage as a result of clamping forces imparted by the clamping mechanism to the bus termination board through the pressure plate member. In particular, the pressure plate member defines a plurality of resistor package pockets for receiving the plurality of spaced resistor packages. The resistor package pockets substantially prevent the clamping forces imparted by the clamping mechanism to the bus termination board from being imparted to the plurality of spaced resistor packages.
In another embodiment, the present invention provides a mounting assembly for providing bus termination of at least one signal line on a printed circuit board (PCB). The mounting assembly includes a connector arrangement, a bus termination board and a pressure plate member. The connector arrangement includes a plurality of electrical interface elements configured to provide electrical communication between the connector arrangement and the at least one signal line of the PCB when the connector arrangement is secured to the PCB. The bus termination board is configured to be received by the connector arrangement. The bus termination board has a first surface that includes a plurality of corresponding electrical interface elements for engaging the plurality of electrical interface elements of the connector arrangement, and a second surface having a plurality of spaced resistor packages for providing bus termination of the signal line of the PCB. The pressure plate member engages the second surface of the bus termination board for protecting the plurality of spaced resistor packages from damage.
This mounting assembly to provide bus termination for a signal line of the present invention makes use of resistor packages surface mounted to a bus termination board to permit mass production and eliminate the need to individually hand load the resistors onto the connector arrangement of the PCB. In addition, the pressure plate member of this bus termination mounting assembly protects these resistor packages from the significant forces, provided by the clamping mechanism, necessary to provide sufficient electrical contact between the resistor packages of the termination board and the connector arrangement of the PCB. Moreover, this bus termination mounting assembly protects the surface-mount resistors from inadvertent damage caused by routine handling of the PCB. Lastly, the bus termination mounting assembly of the present invention is relatively easy and inexpensive to manufacture.